I have a burning/scratching sensation inside the rectum when passing stool. no noticeable blood. occasionally the stool is rather thin shaped. what could it be?

Rectal burning ?'s: Hemorrhoids are herniated blood vessels, with a clot contained , which can alter the diameter of the rectal passage and therefore the form of the stool . See you gyn physician for a rectal exam to be certain.

Proctologist: In my experience proctologists provide are best to diagnose, advise, treat and follow-up on benign anorectal problems like fissures, hemorrhoids, proctitis. Other specialists don't seem as enthused about treating such problems. If your rectal symptoms remain problematic, consult a proctologist.